Coolant circuit in a vehicle

Abstract

Coolant circuit in a vehicle, with a pump (18), an engine (12) to be cooled and a radiator (14), characterized in that a first flow control unit (22) is provided between the engine (12) and the radiator (14) in a main channel (20), which comprises a first valve (32) and a first actuator (30) and which continuously thermostatically controls or regulates a flow of the coolant depending on a temperature of a coolant, and between the engine (12) and the first flow control unit (22) a bypass channel (24) branches off from the main channel (20), which is connected in a fluidically parallel manner to the cooler (14) and opens into the main channel (20) after the cooler (14), wherein a second flow control unit (26) is provided in the bypass channel (24), which comprises a second valve (34) and is designed such that it opens or closes the bypass channel (24) depending on the temperature of the coolant, wherein the first flow control unit (22) functions directly in a temperature-dependent manner and is an electronically controlled throttle thermostat which is coupled to a first temperature sensor (28) which is arranged in the engine (12) or directly downstream of the engine (12) in the direction of flow and detects the temperature of the coolant there, and the other of the flow control units (26) functions indirectly in a temperature-dependent manner and is a passively acting flow control unit which adjusts the flow of the coolant as a result of the flow of the coolant set directly in a temperature-dependent manner by the flow control unit (22) which functions directly in a temperature-dependent manner.

Description

[0001] The invention relates to a coolant circuit in a vehicle, comprising a pump, an engine to be cooled and a radiator.

[0002] To ensure the functionality of a vehicle's engine, it must be continuously cooled once it has reached its operating temperature. For this purpose, typical vehicles are equipped with a coolant circuit, which generally includes a pump, an engine to be cooled, and a radiator. During operation, the pump pumps coolant into the hot engine, where the engine heat is absorbed by the coolant. The heated coolant is then pumped into the radiator, where it is cooled, for example, with air. The cooled coolant is then pumped back to the pump, and the cycle begins again.

[0003] In situations where the engine and coolant are cold (e.g. when starting a vehicle from cold), the rapid warm-up of the engine, which is desired in this situation, is delayed by the coolant circuit described above. For this reason, generic coolant circuits include a thermostat and a bypass line between the engine and the radiator to regulate the coolant temperature, allowing the coolant to bypass the radiator. If the coolant temperature falls below a limit, the main line between the engine and the radiator is closed by the thermostat and the bypass line is opened. This means that the coolant is bypassed the radiator and therefore not cooled. This causes the engine and the coolant to heat up more quickly, which shortens the engine warm-up time.Once the engine and coolant have reached their operating temperature, the thermostat opens the main line at the same rate as it closes the bypass line. As a result, the coolant flows through the radiator, keeping the engine temperature essentially constant.

[0004] DE 100 28 280 A1 discloses a pumping and heating device in a coolant circuit for cooling an engine, in which a thermostatic valve is provided which opens a bypass line when a temperature of the coolant in the thermostatic valve is lower than a certain preset temperature, and closes the bypass line and simultaneously releases a line between the radiator and the engine when the temperature of the coolant in the thermostatic valve is higher than the certain preset temperature.

[0005] DE 41 04 093 A1 shows a cooling system for a vehicle with an internal combustion engine, which has several cooling circuits, each with associated heat exchangers.

[0006] US 2004 / 0079298 A1 describes a circulation system for an internal combustion engine which has a regenerator through which heat can be provided to the engine over a long period of time even when the engine is switched off.

[0007] DE 10 2007 011 673 A1 describes a coolant regulator for a coolant circuit of an internal combustion engine, by means of which a flow of coolant can be regulated depending on the temperature.

[0008] DE 10 2006 051 851 A1 describes a cooling circuit for controlling a cooling system of an internal combustion engine in a vehicle.

[0009] DE 10 2005 018 904 B3 discloses a thermostatic valve for a cooling system of an internal combustion engine, which comprises an expansion element for temperature-dependent flow control.

[0010] DE 20 2008 005 465 U1 shows an overflow valve that is used to protect certain components or assemblies from fluid overpressure.

[0011] From DE 10 2004 058 864 A1 a coolant circuit of an internal combustion engine is known in which a bypass can be opened and closed with a bypass valve in order to change the opening behavior of the thermostat valve.

[0012] DE 101 55 386 A1 discloses a coolant circuit with a double-acting valve that has two locking elements mounted on a drive shaft, which control the bypass flow on the one hand and the cooler flow on the other. Alternatively, two separate valves are provided for this purpose.

[0013] Finally, US 4,369,738 A describes a cooling system for an internal combustion engine comprising a cylinder head with a cooling jacket having an inlet and an outlet, a cylinder block with a cooling jacket having an inlet and an outlet, and a radiator. The cooling system provides either combined cooling for a cylinder head and cylinder block of the engine or partially or completely separate cooling for the cylinder head and cylinder block.

[0014] In generic coolant circuits, a two-way thermostat is typically used to regulate the coolant temperature as described above. However, the location of such a two-way thermostat in the engine compartment is limited, as it must be located either close to the engine or close to the radiator to simplify the layout of the bypass line.

[0015] The object of the invention is to provide a simple coolant circuit with an integrated bypass line, which avoids the aforementioned disadvantages of generic coolant circuits.

[0016] This object is achieved according to the invention by a coolant circuit in a vehicle having the features of claims 1 and 3.

[0017] In the coolant circuit according to the invention, two spatially separated flow control units are provided instead of a two-way thermostat. This allows for greater design freedom in the arrangement of components in the engine compartment. The use of two flow control units also makes it possible to independently control or regulate the coolant flow in the main channel and bypass channel depending on the engine operating state (coolant temperature, engine speed, etc.). The second flow control unit actively opens or closes the coolant flow through the bypass channel indirectly depending on the coolant temperature. This means that the second, passively acting flow control unit adjusts the coolant flow through the bypass channel as a result of the coolant flow set by the first flow control unit as a function of the temperature.By using two flow control units instead of a two-way thermostat, the design of the coolant circuit according to the invention can be designed and adapted significantly more flexibly. The first flow control unit is an electronically controlled throttle thermostat coupled to a first temperature sensor located in the engine or immediately downstream of the engine, where it detects the coolant temperature.

[0018] According to a second aspect of the invention, the first flow control unit and the second flow control unit are each an electronically controlled throttle thermostat, wherein both throttle thermostats are coupled to a first temperature sensor which is arranged in the engine or in the direction of flow immediately after the engine and detects the temperature of the coolant there, wherein the flow control units are coupled to one another in such a way that opening one flow control unit causes the other flow control unit to close to the same extent.

[0019] A common temperature sensor that measures the coolant temperature in one area for both flow control units simplifies the design of the coolant circuit and minimizes the number of required components. This temperature sensor is an electronic sensor that electronically controls the actuator of each flow control unit.

[0020] According to a further aspect, the first temperature sensor is arranged in the engine or immediately downstream of the engine in the direction of flow, where it detects the coolant temperature. By arranging the temperature sensor in the engine or near the engine, it is possible to detect the hottest temperature in the coolant circuit.

[0021] Preferably, the first valve of the first flow control unit is in a maximally closed position at low coolant temperatures, in particular lower than 80°C, and in a maximally open position once an operating temperature of the coolant is reached, in particular above 95°C, wherein the first valve is moved continuously into intermediate positions between the two maximum positions depending on the temperature of the coolant at the first temperature sensor. Thus, at low coolant temperatures, coolant is no longer fed into the radiator, which means that the coolant is not additionally cooled in the radiator, whereby the warm-up time of the engine can be significantly reduced. Once the operating temperature of the coolant is reached, a maximum flow to the radiator is ensured, whereby the coolant is constantly cooled in the radiator and thus a substantially constant operating temperature of the coolant can be ensured.The continuous movement of the first valve in intermediate positions between the two maximum positions also helps to keep the operating temperature of the coolant essentially constant.

[0022] Preferably, the second valve of the second flow control unit is in a maximum open position at low coolant temperatures, in particular lower than 80°C, and in a maximum closed position once an operating temperature of the coolant is reached, in particular above 95°C. At low coolant temperatures, the coolant is thus guided through the bypass channel past the radiator and back to the engine. This short-circuited coolant circuit heats the coolant significantly more quickly and consequently shortens the warm-up time of the engine. Once an operating temperature of the coolant is reached, the bypass channel and thus the short-circuited coolant circuit are closed by the second valve, whereby the maximum available coolant flow can now be guided to the radiator in the main channel.

[0023] An embodiment not forming part of the invention provides that the second flow control unit has an expansion thermostat. When using one thermostat per flow control unit (e.g., one expansion thermostat in the first flow control unit and one expansion thermostat in the second flow control unit), it can be provided that the two flow control units can communicate with each other electronically or mechanically such that when the valve of one flow control unit closes, the valve of the other flow control unit opens to the same extent. This is also conceivable for the other embodiments.

[0024] A further embodiment provides that the second valve of the second flow control unit is a pressure valve, in particular a pressure relief valve. Thus, the flow of the coolant through the bypass channel is not regulated thermostatically by the second flow control unit, but rather with a pressure valve. The second flow control unit is therefore indirectly temperature-dependent. At low coolant temperatures, the flow in the main channel is closed by the first flow control unit, which leads to the coolant pressure upstream of the closed valve of the first flow control unit increasing until it exceeds a preset limit and the pressure valve is thereby opened. If the closed valve of the first flow control unit is opened due to an increase in the coolant temperature, the pressure on the pressure valve decreases, causing it to close.Purely mechanical pressure valves are reliable and have already proven themselves. They are also simple to construct, as they do not require a pressure or temperature sensor or actuator.

[0025] According to the embodiment according to claim 3, the first flow control unit and / or the second flow control unit each have a throttle thermostat. The two flow control units are in direct communication. Generally, with a throttle thermostat, the flow of the coolant is throttled until the desired opening temperature provided in the thermostat is reached. Only then, again via the temperature, does the valve open, allowing the flow of the coolant.

[0026] In another embodiment of the coolant circuit, an oil-coolant heat exchanger is provided. The integration of the oil-coolant heat exchanger can lead to a further improvement in engine warm-up.

[0027] Further advantages and features of the invention will become apparent from the following description and the drawings, to which reference is made. In the drawings: - Fig. 1 shows a schematic structure of a first embodiment of a coolant circuit not belonging to the invention, - Fig. 2 shows a schematic structure of a second embodiment of the coolant circuit according to the invention, - Fig. 3 a schematic structure of a third embodiment of the coolant circuit according to the invention, and - Fig. 4 shows a schematic structure of an embodiment of a coolant circuit which no longer falls within the scope of the claims.

[0028] The Fig. The coolant circuit 10 shown in Figure 1 comprises an engine 12, a radiator 14, an oil-coolant heat exchanger 16, and a pump 18. A main channel 20 fluidly connects the engine 12 to the radiator 14, the radiator 14 to the oil-coolant heat exchanger 16, the oil-coolant heat exchanger 16 to the pump 18, and the pump 18 to the engine 12.

[0029] A first flow control unit 22 is provided between the engine 12 and the cooler 14.

[0030] Between the motor 12 and the first flow control unit 22, a bypass channel 24 branches off from the main channel 20. The bypass channel 24 is connected in parallel to the cooler 14 and flows into the main channel 20 after the cooler 14.

[0031] A second flow control unit 26 is arranged in the bypass channel 24.

[0032] The two flow control units 22, 26 are arranged positionally and fluidically distant from each other in the coolant circuit 10.

[0033] In the embodiment shown here, the first flow control unit 22 comprises a first integrated temperature sensor 28, a first actuator 30 and a first valve 32, all of which are integrated in the first flow control unit 22.

[0034] The first temperature sensor 28 can, for example, be an electronic temperature sensor that electronically controls the first actuator 30.

[0035] Optionally, the first temperature sensor 28 can also be part of the first actuator 30, which mechanically or, in particular, thermomechanically controls or regulates the first valve 32, e.g., by a pressure sensor simultaneously acting as the actuator 30. The first temperature sensor 28 is integrated into the first actuator 30, so that the first actuator 30 itself senses the temperature of the coolant, and thus the first temperature sensor 28 is no longer an additional external component. For the sake of simplicity, the actuator and the temperature sensor associated with the actuator are referred to as two separate components in the present application.

[0036] The first valve 32 is coupled to the first actuator 30 and is continuously adjusted by the first actuator 30 depending on the coolant temperature.

[0037] Since in the first flow control unit 22 the first valve 32 is adjusted based on the temperature of the coolant measured by the first temperature sensor 28, the first flow control unit 22 is directly dependent on the temperature of the coolant.

[0038] The first flow control unit 22 can be designed as an expansion thermostat (e.g. wax actuator) and in particular as a throttle thermostat.

[0039] The second flow control unit 26 comprises a second valve 34 which is biased by a spring 36 against a flow direction of the coolant.

[0040] The second valve 34 can be designed as a purely mechanical pressure valve and in particular as a pressure relief valve.

[0041] Since the second flow control unit 26 does not include a temperature sensor that measures the temperature of the coolant and controls or regulates the flow of the coolant based on this temperature, the second flow control unit 26 is indirectly dependent on the temperature of the coolant. In other words, the second flow control unit 26 is influenced by a flow change triggered by the adjustment of the first valve 32 of the first flow control unit 22, which is dependent on the temperature of the coolant, and is a passively operating flow control unit.

[0042] In the Fig. In the situation illustrated in Figure 1, the coolant is cold, such as occurs during a cold start of a vehicle. In the embodiment described here, the first flow control unit 22 comprises an expansion thermostat, in particular a throttle thermostat, e.g., with a wax actuator.

[0043] The first actuator 30 is therefore not controlled externally and detects the temperature of the coolant “by itself” and adjusts the first valve 32 accordingly.

[0044] As long as the coolant temperature is below a certain preset limit (e.g., 80 °C), the first valve 32 is in a fully closed position. Consequently, the flow of coolant to the radiator is blocked, and the coolant accumulates in front of the first valve 32.

[0045] This leads to an increase in pressure upstream of the first flow control unit 22 and upstream of the second flow control unit 26. As soon as the pressure upstream of the first flow control unit 22 exceeds a certain limit value, which can be adjusted, for example, by the preload force of the spring 36, the second valve 34 opens and the coolant can flow through the bypass channel 24.

[0046] After the bypass channel 24, the coolant flows into the main channel 20 after the radiator 14 and is pumped further into the oil-coolant heat exchanger 16. There, a heat exchange between the oil and the coolant can take place.

[0047] The coolant is then directed to pump 18, where it is pumped further into the engine 12. There, heat transfer takes place from the warming engine 12 to the cooler coolant.

[0048] The heated coolant then flows to the first flow control unit 22 and the second flow control unit 26. If the coolant has not yet reached the temperature limit, the first valve 32 remains closed. As long as the first valve 32 is closed, the coolant circulates in the short-circuited coolant circuit via the bypass channel 24 past the radiator 14.

[0049] Once the lower coolant temperature limit is reached, the first actuator 30 continuously opens the first valve 32 of the first flow control unit 22, allowing a partial flow of coolant to the radiator 14. There, the coolant is cooled and mixes with the warmer coolant after the bypass channel 24 opens into the main channel 20. This reduces the heating of the coolant in the short-circuited coolant circuit.

[0050] Once a predetermined operating temperature of the coolant is reached (e.g. 95 °C), the first valve 32 is in a maximum open position, whereby no more coolant accumulates in front of the first flow control unit 22 and the second flow control unit 26 and, as a result, the pressure in front of the second flow control unit 26 falls below a limit value at which the tension force of the spring 36 is greater than the pressure generated by the coolant on the second valve 34. As a result, the second valve 34 is in a maximum closed position and the flow of coolant through the second flow control unit 26 is prevented.

[0051] The entire coolant volume flow now flows in the main channel 20 via the cooler 14. The coolant is thus continuously heated in the engine 12 and cooled in the cooler 14, whereby the coolant temperature can be kept constant.

[0052] In Fig. 2 shows an embodiment of the coolant circuit 10' which is essentially identical to that shown in Fig. 1. Therefore, we will not repeat the explanation of the same components.

[0053] In the coolant circuit 10' from Fig. 2, the flow control units 22, 26 are constructed differently.

[0054] In the embodiment shown here, the first temperature sensor 28 is no longer integrated in the first flow control unit 22, but is positioned remote from the first flow control unit 22 in the motor 12.

[0055] It is advantageous to arrange the first temperature sensor 28 in the engine 12 or immediately downstream of the engine 12, since this makes it possible to detect the warmest coolant temperatures.

[0056] The first actuator 30 is electronically controlled by the first temperature sensor 28, which can be designed, for example, as an electronic temperature sensor, via a signal transmission 38, which can in particular be unidirectional.

[0057] The opening and closing of the first valve 32 takes place as already described for the coolant circuit 10 of the Fig. 1, continuously and directly dependent on the temperature of the coolant.

[0058] In the coolant circuit 10', an electronically controlled pressure valve is used instead of a mechanical pressure valve. In the embodiment shown here, the pressure is measured by a pressure sensor 40 upstream of the second flow control unit 26.

[0059] A second actuator 44 is controlled by the pressure sensor 40 via a signal transmission 42, which can in particular be unidirectional.

[0060] The second flow control unit 26 can be designed such that it operates only in two operating states (open or closed), ie when a certain preset limit value is undershot or exceeded, the second flow control unit 26 is closed or open, respectively.

[0061] Optionally, the second valve 34 of the second flow control unit 26 can be continuously closed or opened between a lower pressure limit and an upper pressure limit.

[0062] The pressure sensor 40 can be freely positioned between the motor 12 and the first flow control unit 22 or the second flow control unit 26.

[0063] The first flow control unit 22 and the second flow control unit 26 can each be designed as an electronically controlled throttle thermostat.

[0064] In the situation shown here, the engine 12 and the coolant are at operating temperature. The flow through the first flow control unit 22 to the radiator 14 is open, and the flow through the bypass channel 24 is closed by the second flow control unit 26.

[0065] The Fig. The coolant circuit 10" shown in Figure 3 is essentially similar to the coolant circuits 10, 10' shown previously, which is why a repetition of the explanation of the same components will be omitted below.

[0066] In the embodiment of the coolant circuit 10" shown here, the first temperature sensor 28 is assigned to the first flow control unit 22 and the second flow control unit 26.

[0067] The first actuator 30 and the second actuator 44 are each electronically controlled by a signal transmission 38 from the first temperature sensor 28. The first temperature sensor 28 is positioned in the motor 12 and can be implemented, for example, as an electronic temperature sensor.

[0068] Optionally, the first temperature sensor 28 can be positioned immediately after the motor 12.

[0069] A second temperature sensor 48, which is assigned to the second flow control unit and is also positioned in the motor 12 or immediately after the motor 12, would also be conceivable.

[0070] The first flow control unit 22 and the second flow control unit 26 can each be designed, for example, as a throttle thermostat.

[0071] The two flow control units 22, 26 are optionally in a communication connection 46. This means that the two flow control units 22, 26 can exchange information about their status (e.g. degree of opening) in particular bidirectionally.

[0072] This makes it possible to coordinate the opening and closing of one flow control unit with the closing and opening of the other flow control unit. For example, when the first valve 32 of the first flow control unit 22 opens, the second valve 34 of the second flow control unit 26 is closed to the same extent.

[0073] If such a communication connection 46 is present, both flow control units 22, 26 do not need to be connected to the first temperature sensor 28 via the signal transmission 38. It is sufficient if only one flow control unit is connected to the first temperature sensor 28 via the signal transmission 38 and communicates its status with the other flow control unit via the communication connection 46.

[0074] In the embodiment shown here, the opening and closing of the valves 32, 34 of the flow control units 22, 26 takes place continuously and directly dependent on the temperature of the coolant.

[0075] The Fig. The coolant circuit 10''' shown in Figure 4 is essentially similar to the previously shown coolant circuits 10, 10', 10'', which is why the explanation of the same components will not be repeated in the following.

[0076] In the coolant circuit 10''', the first temperature sensor 28 is integrated into the first flow control unit 22, and a second temperature sensor 48 is integrated into the second flow control unit 26. Both temperature sensors 28, 48 thus measure the temperature of the coolant in the immediate vicinity of the respective flow control unit 22, 26.

[0077] The two flow control units 22, 26 can each be designed as an expansion thermostat (e.g. throttle thermostat).

[0078] The temperature sensors 28, 48 are integrated in the respective actuator 30, 44, so that the actuators 30, 44 sense the temperature of the coolant “themselves” and, depending on this, continuously adjust the valve 32, 34 assigned to them.

[0079] Consequently, the two flow control units 22, 26 are directly dependent on the temperature of the coolant.

Claims

[1] Coolant circuit in a vehicle, with a pump (18), an engine (12) to be cooled and a radiator (14), characterized by , that a first flow control unit (22) is provided between the engine (12) and the radiator (14) in a main channel (20), which comprises a first valve (32) and a first actuator (30) and which continuously thermostatically controls or regulates a flow of the coolant depending on a temperature of a coolant, and between the engine (12) and the first flow control unit (22) a bypass channel (24) branches off from the main channel (20), which is connected in a fluidically parallel manner to the cooler (14) and opens into the main channel (20) after the cooler (14), wherein a second flow control unit (26) is provided in the bypass channel (24), which comprises a second valve (34) and is designed such that it opens or closes the bypass channel (24) depending on the temperature of the coolant, wherein the first flow control unit (22) functions directly in a temperature-dependent manner and is an electronically controlled throttle thermostat which is coupled to a first temperature sensor (28) which is arranged in the engine (12) or directly downstream of the engine (12) in the direction of flow and detects the temperature of the coolant there, and the other of the flow control units (26) functions indirectly in a temperature-dependent manner and is a passively acting flow control unit which adjusts the flow of the coolant as a result of the flow of the coolant set directly in a temperature-dependent manner by the flow control unit (22) which functions directly in a temperature-dependent manner. [2] Coolant circuit according to claim 1, characterized by that the second valve (34) of the second flow control unit (26) is a pressure valve, in particular a pressure relief valve. [3] Coolant circuit in a vehicle, with a pump (18), an engine (12) to be cooled and a radiator (14), characterized by , that a first flow control unit (22) is provided between the engine (12) and the radiator (14) in a main channel (20), which comprises a first valve (32) and a first actuator (30) and which continuously thermostatically controls or regulates a flow of the coolant depending on a temperature of a coolant, and between the engine (12) and the first flow control unit (22) a bypass channel (24) branches off from the main channel (20), which is connected in a fluidically parallel manner to the cooler (14) and opens into the main channel (20) after the cooler (14), wherein a second flow control unit (26) is provided in the bypass channel (24), which comprises a second valve (34) and is designed such that it opens or closes the bypass channel (24) depending on the temperature of the coolant, wherein the first flow control unit (22) and the second flow control unit (26) are each an electronically controlled throttle thermostat, wherein both throttle thermostats are coupled to a first temperature sensor (28) which is arranged in the engine (12) or in the direction of flow immediately after the engine (12) and detects the temperature of the coolant there, wherein the flow control units (22, 26) are coupled to one another in a direct communication connection (46) and in such a way that opening one flow control unit (22, 26) causes the other flow control unit (22, 26) to close to the same extent. [4] Coolant circuit according to claim 3, characterized by that the two flow control units (22, 26) can bidirectionally exchange information about their opening state. [5] Coolant circuit according to one of the preceding claims, characterized bythat the first valve (32) of the first flow control unit (22) is in a maximum closed position at low coolant temperatures, in particular lower than 80°C, and is in a maximum open position upon reaching an operating temperature of the coolant, in particular from 95°C, wherein the first valve (32) is moved continuously into intermediate positions between the two maximum positions depending on the temperature of the coolant at the first temperature sensor (28). [6] Coolant circuit according to one of the preceding claims, characterized by that the second valve (34) of the second flow control unit (26) is in a maximum open position at low coolant temperatures, in particular lower than 80°C, and is in a maximum closed position once an operating temperature of the coolant is reached, in particular from 95°C. [7] Coolant circuit according to one of the preceding claims, characterized bythat an oil-coolant heat exchanger (16) is provided.

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